


Untouchable

by mebsuta



Series: Sacrosanct [1]
Category: Sherlock (TV)
Genre: M/M, Other Additional Tags to Be Added, Shota, Shota!Jim, Underage - Freeform
Language: English
Status: Completed
Published: 2015-05-26
Updated: 2015-06-30
Packaged: 2018-04-01 10:18:02
Rating: Explicit
Warnings: Underage
Chapters: 3
Words: 4,852
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4015999
Author URL: https://archiveofourown.org/users/mebsuta/pseuds/mebsuta
Summary: <blockquote class="userstuff">
              <p>Not once had they ever asked for a favour, not in 11 years and now he was babysitting their brat. Sebastian needed some new friends.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Heed the tags and heed the warnings. Do not proceed if you don't want to read it. Rating and warnings for chapter 2 (and onwards if there is any more added)

Sebastian sometimes hated his friends. He hated having friends at all because they always expected fucking favours which is why he had ended up sleeping on his own couch in his own fucking flat with some brat sleeping in his bed.  
He didn’t have plans that evening anyway but it simply wasn’t the point he had infinitely better things to be doing than looking after a friends kid when they were out and hoping to shag the missus that night.

He groaned and rolled over, settling on his side. He had slept in much worse conditions in the army granted but now he was used to his own bed in his own flat but he couldn’t bloody sleep there. He let out another frustrated huff as he sat up and switched the TV on.  
It was hardly better than wallowing in his own self-pity, that evening had consisted of an hour of shit cartoons before putting the kid to bed and he could honestly never see himself with a child of his own. Though knowing him he probably had some poor kid out there with a struggling singly mother but he gave it no more thought as he found a show he would actually want to watch.

He still couldn’t believe it had been 10 years and not once had he had to deal with any form of ‘babysitting’ and now he was looking after Jim, the worst thing was how annoyed he was by it. All he would have done that evening is treat himself to a few (or more) glasses of scotch and the same shit TV he had on now but he at least _enjoyed_ his own company.  
He huffed as he settled back onto the sofa, the blanket draped around his bare shoulders to stave off the chill, the sweat pants keeping his legs warm. He held the remote in one hand as he continued to flick through the channels and finally settled on a game show marathon.

He must have been about half an hour into the first show before he heard the soft padding of feet coming down the hallway, anyone else would have missed it even with the TV on low but he still retained more than a few habits from his army days and his awareness was certainly one of them, even this late and even when he was this annoyed.

He remained focused on the TV until the kid was practically right in front of him and his soft voice was filling the room along with the sound of the telly in the background.

“I can’t sleep Seb.” Sebastian tried not to roll his eyes at that nick name coming from the kid’s mouth but he tended to stumble around his long name so he didn’t really have a choice. He also didn’t really know what do; he had never had any experience with dealing with someone this young (well there was that 14 year old in Thailand but that was a whole ‘nother type of ‘dealing with’).

“Uhm, do you wanna watch some TV kid?” He saw the small nod of Jim’s head and he panicked for a moment, trying to think back of what was done when he was younger and he vaguely remembered sitting on the nanny’s knee and it used to cheer him up.  
“Come here then, you can’t exactly stand there and watch it.” He felt kind of… happy when he saw the small smile Jim gave at the comment, obviously he had said something right and he opened his arms, gesturing for Jim to come over.

The child took a few tentative steps forward before finally deeming Sebastian to be okay and climbing, quite literally into his lap. He nearly got kneed in the groin when he climbed up and he was ready to push the kid off before he finally settled and managed to cuddle up to Sebastian.  
This time he did roll his eyes and shrugged lightly before wrapping his large arms around the boy, looking down and almost immediately becoming fascinated by how small Jim was compared to himself.

Jim was overly slim but in a willowy pleasing sort of way, not holding much puppy fat at all for someone of his age except for the youthful roundness to his face. Sebastian though he felt almost fragile because he was so small, now encircled by large arms, and he gave him one last glance before turning back to the TV.  
It felt strange having someone else in the flat with him, never mind someone in his lap. If there was anyone in the flat with him they were usually ‘preoccupied’ and Sebastian always kicked them out afterward, not wanting to deal with talking in case they decided to try and rope him into a second endeavour.

He had a rule, never the same person twice. It always got too messy, too much to deal with and it was rare anyone could put up with Sebastian for that long regardless. Yet, it was still comforting having the small weight on his lap, now cuddled against him and it… well it was unusual yes but it was nice, in a way.

It wasn’t like the young Thai kid who he only held when he was holding them down, getting the most of the money he had paid, this was slightly protective. His arms were now wrapped properly around Jim and one thumb was gently stroking the boy’s shoulder which he obviously appreciated as he gave a contended little murmur.  
Sebastian sighed in contentment himself, surprised by the action but not entirely against it. It was a few moments later when he realised how late it must be and he knew the kid should be sleeping by now.

“Do you wanna go back to bed Jim?” He felt a small nod against his chest and he went to shift the boy from his lap before realising he was just a kid and he could easily lift him up. He wrapped his arms more firmly around Jim and the little boy’s arms came up to circle his neck as he stood up, lifting him effortlessly.  
He walked him through to the bedroom, balancing him precariously on one arm while he pulled back the quilt so he could lay Jim back in the bed and hopefully this time he would actually sleep.

What Sebastian wasn’t expecting him however was for Jim's grip around his neck to remain as he tried to stand back up so he could go into the living room. He tried to pry Jim’s arms from him but as soon as he lightly grasped Jim’s wrists he was met with a murmur of discontentment.

“Do you want me to stay?” Jim nodded, his hair tickling Sebastian’s neck and the man sighed heavily, this was by far the most inconvenient thing he ever had to do yet he slid into the bed next to Jim. He assumed the boy must usually have something to ‘cuddle’ at home and had forgotten to bring it so now Sebastian became the substitute. This was it, his life now a human fucking teddy.

“Get some sleep now ‘kay? It’s late.” Sebastian lay rather still as Jim tried to get comfortable, very nearly climbing on top of him until he was using Sebastian’s chest as a pillow and he thankfully fell asleep almost immediately.  
Soft breaths filled the room and Sebastian watched Jim's face for a few moments until he simply couldn’t help himself from bringing a hand up and stroking it lightly through Jim’s hair, it was overly soft and he played with the strands for a few minutes before finally drifting off himself.


	2. Chapter 2

**Notes for the Chapter:**

> This was meant to be two chapters but it's now turning into three, maybe four and it might get a sequel... perhaps.

Sebastian slept pretty solidly, another habit he had retained from the army, when he slept his body made the most of it which is why he was surprised when he was woke up by someone shifting beneath the covers.   
He was fairly sure he hadn't been out last night on the pull so he didn't bring anyone home, he knew he hadn't paid for a whore or else they would be gone by now.   
  
His eyes suddenly jolted open when he felt his pants being tugged down impatiently and he flung back the quilt to find large brown eyes looking up at him and he was rather... Confused.  
Yes he remembered taking the boy to bed and ended up becoming some kind of substitute fucking Teddy but firstly why was Jim tugging his pants off and secondly why wasn't he stopping him?   
  
"Jim? What are you doing?" Jim continued to stare at him with wide eyes, which was rather unsettling, before he gave a loud gasp as a small finger prodded at his flaccid cock.   
  
"Your penis is bigger. It got bigger in the night and now it's not as big. But it's still bigger than mine." Sebastian groaned internally, it was borderline mortifying that he suddenly had to try and talk about this to a 10 year old and he hurriedly tried to think of an answer.   
Before he could even start to form an answer someone so young could understand he felt a finger prod at him again before prodding his sac.   
  
"Jesus Christ, stop it." He took a breath and licked his lips before trying to explain, he knew Jim wasn't exactly stupid for a child but he also know he would have to explain it in layman's terms too, God he was so out of his depth.  
"Well, mines bigger because I'm a fully grown man and sometimes some men have bigger penises and some men have smaller ones it can change. And it gets bigger when you get uhm... Aroused."   
  
"Why did you get aroused when you were asleep?"   
  
"Well, sometimes people have dreams about things that arouse them and it ends up... Exciting their body and their penis gets hard." Sebastian winced at the way he was talking, it sounded so fucking weird coming from his mouth and he looked down at Jim, hoping he had explained everything to the kid who was uncomfortably close to his cock.   
  
"Sometimes that started happening to mine. It feels funny when I touch it when it's _aroused_." Jim drew out the words, almost like he was seeing how it felt on his tongue before narrowing his eyes at Sebastian.   
"I want to see. I want to see it get bigger."   
  
"No kid, that's gonna stop there. No fucking way."   
  
"Why!?" Sebastian gave Jim a disbelieving look and an exasperated sigh; his parents were obviously fucking useless if they hadn't had 'the talk' with him if he was curious already.   
  
"Because it's not right!" Jim just looked up to him and reached forward prodding the flaccid member again before shuffling forward and taking it gently in one hand, moving it around and looking closely like he was examining it.   
  
"Why is it not right? You're just teaching me."   
  
"It's not right because I'm a grown man and you're still a kid, you shouldn't be touching me like that." Despite his words Sebastian's body tried to start reacting to the physical stimuli and he mentally told the arousal to fuck off.   
"Get off Jim."   
  
"Please! I just want to learn, think of something that makes you excited. I just want to see, just once. It's only a penis." Sebastian wanted to cry when Jim told him to think of something that makes him excited and he immediate thought of the boy right in front of him who had his small hand still exploring over his groin but he shook his head.   
  
"Jim that's not the point, it's because what's you're doing is an adult thing. Adults get each other aroused and pleasure each other but not someone as young as you, not with someone you're own age never mind my age."   
  
"I won't tell, pleaseeee." By now Jim's voice was a whine and he closed his eyes for a moment, ready to count backwards from ten but suddenly his eyes flew open and he gave a gasp as little fingers squeezed around him and stroked slightly.   
"That's what feels funny when I do it to my own penis. Like, when it gets bigger and sometimes it feels like I need to use the toilet so I stop and it goes away."   
  
Sebastian shook his head, those innocent words, that sentence should not have been what truly sent the blood rushing to his groin but damn him, it was and if he wasn't already going to hell he just booked fast track.   
  
"Fine, fuck. Don't dare speak a word of this to _anyone_ and I'm only going to let you see it get 'bigger' okay?" Jim nodded, a bright smile suddenly on his face and Sebastian pulled the kids little hand away before wrapping his own around the soft flesh and starting to stroke, trying to think about something to get him hard and he shivered as yet again he thought about the boy in front of him.   
  
Jim watched intently, wide eyes slightly full of wonder because he was seeing new things and he suddenly knocked Sebastian's hand away, replacing it with his own. The small fingers could barely form a proper circle around it even when it was flaccid and it was now starting to fill.   
  
"Jim... What are you doing. I said I would show you."   
  
"I want to do it!" Sebastian groaned in frustration and then in reluctant pleasure as Jim started moving his hand. It was jerky, hardly skilled but he looked down and saw a little pink tongue peak out between Jim lips in concentration and it only made the blood rush faster.   
He dropped his head back and sighed, this was so fucking wrong but Jim looked so perfect between his legs, framed by large muscular thighs and a few moments later his breathing had picked up slightly and he was fully hard.   
  
"Right, you can get off now Jim." The kid bit his lip and looked up at Sebastian before pulling his hand back slowly.   
  
"But I have more questions, can I look properly?" Sebastian rolled his eyes, looking back down at Jim and when he saw the large eyes he found himself nodding despite how ridiculous he felt.   
He was also still in slight shock from the fact he had just let his friends son bring him to full hardness and he had fucking enjoyed it.   
  
"What do you wanna know?" Jim leaned forward, his face almost _too_ close to Sebastian's groin as he brought both of his hands up to wrap around the length, barely covering it and he frowned as if he was considering the size.   
  
"When you stroke it like I do sometimes does it feel like you want to pee?" Sebastian tried not to laugh at the innocent question which wasn't difficult since he was distracted by Jim's hands.   
  
"It feels different, it feels good you just have to get used to the sensation." Sebastian watched as one of Jim's hands moved up and he touched his fingertips to the glans, making Sebastian suck in a sharp breath and try to hold back a shudder.   
  
"It's a different shape. Does that feel good, you made a noise when I touched you there."   
  
"It's very sensitive and can feel good yes, and everyone is different. Different shapes and sizes." Jim nodded and moved his hand back down, one still holding the middle of the shaft as he ran little fingers through the dark blond hairs at the base.  
  
"I don't have any hairs. Do some people not get hairs?"   
  
"Everyone gets hairs; you will get them when you get older, but yours will be darker, like the hairs on your head." He couldn't help but reach down to stroke his fingers through Jim's hair, just to prove his point of course.   
Jim looked up at him and hummed, nodding before he squeezed his hand lightly making Sebastian swear.   
  
"Shit, Jim what are you doing."   
  
"Exploring?" He made it sound like a question and Sebastian groaned, this kid was gonna be the death of him.   
"So after you get... Aroused does it just go away? What do you do? What's the point if it just goes away?" Sebastian was hoping Jim would leave it there but no he had to go and ask the most awkward question possible and he would be expecting an answer.   
  
"Well uhm, it doesn't usually go away. So, er if you get aroused you can... Pleasure yourself or if you're with a partner they do it for you and you end up having an uhm orgasm." He thought he done a good job of explaining it and he let out a relieved breath when he saw Jim nodding that he understood but he froze when Jim made his next demand.   
  
"I want to see." 

**Notes for the Chapter:**

> thank you for reading, comment, kudos and all that jazz :)


	3. Chapter 3

“No fuckin’ way kid. That was too far as it is and it’s gonna stop right now.” 

“No! I. Want. To. See!” The sheer brattish tone made Sebastian’s eyebrows rise in shock as Jim looked up at Sebastian's face and tried to look as put out as he possibly could, he was positively hungry for new information and this was definitely new.  
Even better, he seemed to be winding Sebastian up at the same time and it was fun too, especially if he got to have a go himself. 

"Please, I don't understand why you won't let me see?" He pouted slightly, trying not to smile as Sebastian's eyes were drawn to his lips. "Is it bad? I won't tell anyone Seb I promise, I really do promise."  
Sebastian didn't know what to do at all, he knew, he knew he shouldn't but what if it was just once? Just once to show Jim what he wanted and then they would never talk of it again, it would never be mentioned again and he could go back to living his live, drinking and fucking and Jim could go back to being a kid. 

"If I show you, and I mean if, you cannot tell anyone. Not a single person okay?" Sebastian licked his lips nervously and was annoyed at himself when he looked down and his erection was still as solid as ever.  
He moved his eyes to Jim who was now staring rather unsettlingly at his cock as he nodded and Sebastian moved his free arm to the side, making a sort of cradle shape for Jim to settle in. 

"Come here." He told himself that he was pulling Jim closer so he wasn’t put off by the intent staring but he knew it was truly because he wanted Jim closer, smiling as the kid moved up and settled by his side.  
Jim settled down with his head on Sebastian's chest, a grin on his face as he made himself comfortable and he quickly glanced up to Sebastian’s face before looking back down. 

"Go on then! Pleaseeee I want to see!" Sebastian shook his head in disbelief, sent a quick apology to a god he didn't even believe in and took himself in hand, groaning almost immediately.  
He rarely got himself off, easily getting bored by his own hand but this, this was different and he placed his free hand on Jim's waist where the boy was settled against his side. For comfort purposes of course... 

"So, so ah~ if you're with a partner, they will d-do this for you or you will do it for them." Sebastian had let his eyes fall shut and was completely unaware of how his thumb was rubbing over the soft skin on Jim's side as he stroked himself slowly. 

"What do you think about? Do you think about things when you do it?" Jim's question sounded innocent enough but he was sure he could hear the traces of a smirk in the young voice as he kept his eyes closed.  
He tried to ignore the question, he did but the silence after the words almost felt too awkward only filled with the sounds of his own quiet gasps and the movement of his hand so he deigned to give Jim a reply.

"I think about, I think about things I find attractive. Sometimes I, ah~ I barely think at all. I focus on the sensation." Jim hummed and nodded, not tearing his eyes away from where Sebastian's hand was moving over the large penis and Jim finally moved forward and pressed his finger to the tip, pulling it away and holding it up to his face. 

"What's this?" Sebastian hated that he shuddered at the thought that Jim wasn't even developed enough to produce pre-cum and he didn't know what third dimension he had to be in to find that incredibly arousing but his cock still twitched in his hand. 

"It's uh pre-cum, I mean pre-ejaculate." He closed his eyes and tipped his head back, still unaware of his hand rubbing over Jim's side.  
"When you orgasm, when you're fully developed you ejaculate properly, about, maybe a teaspoon or tablespoon full or something." Sebastian couldn't help but moan as he gave his prick a firm squeeze, rubbing his own thumb over the tip. 

"Is that why it feels like you're gonna pee? Cause something comes out?" Jim had moved further down, to get a closer look and before Sebastian's could even answer a little hand had wrapped itself around the area at the top of his cock where his own hand couldn't cover. 

"J-Jim, what are you doing?" He groaned deep when Jim moved his inexperienced hand jerkily over his flesh and squeezed Jim's side. 

"I'm helping! I like the noises you make." Sebastian suddenly knocked Jim's hand away and moved back, making sure there was some distance between them. 

"No! No Jim. This is too wrong, this shouldn't be happening." 

"I won't tell anyone I promise!" He moved forward and went to touch Sebastian again but promptly had his hand slapped away and he pouted immediately, making sure his lower lip wobbled slightly. 

"No Jim." 

"Please! I promise I won't tell, I will be a good boy!" That sentence right there, that sentence was what done Sebastian in and something took over. He should have been scared of the change, he knew he should have been concerned with the way his mind shifted, the way he thought about Jim but he didn't care. 

"Come here." Sebastian's voice was slightly gruff and Jim had to bite back a grin, he had gotten his way and it made him happy. He also got to see... Maybe experience, something new.  
Jim moved further forward, moving closer to Sebastian and he licked his lips, smiling when a large hand covered his own and guided it back to the hard flesh resting heavy on Sebastian's stomach. 

Jim's hand barely wrapped around Sebastian's girth and it was completely engulfed by Sebastian's own hand but the raven haired boy still smiled. This was new, this was new and he was enjoying it immensely.  
He move his fingers, squeezing lightly and drawing a gasp from the man before Sebastian tightened his own grip and started to stroke. 

"When will you orgasm?" The question seemed to bring Sebastian back to himself a small bit but he didn't stop stroking and he looked Jim directly in the eye, a big mistake because he cock twitched hard and he bit his lip. 

"Too fucking soon kid." Sebastian kept up the firm and rhythmic movements, still uncomprehending about how his friends fucking kid currently had his small hand wrapped around his large prick but he was quite past the point of caring. 

"Can I orgasm after you?" The question made Sebastian bite his lip hard, to the point he nearly drew blood. His mind suddenly brought up images of Jim squirming beside him as he large hand easily covered Jim's small prick.  
He imagine the face Jim would make when he finally climaxed, he was sure it wouldn't take him long at all and he imagined plush pink lips parting in a cry and large eyes squeezing shut as his small body shook under his hand. 

"Oh fucking hell, I'm close." Sebastian threw his head back, trying not to think of the small hand under his but if anything the thought only made him closer and he felt the tension starting in the pit of his stomach.  
It soon started to coil into a tense heat as he shuddered and his hips thrust up of their own accord. He squeezed his hand around Jim's and with a gasp that faded into a deep groan he was spilling his release onto his stomach. 

He trembled slightly and his hips thrust erratically for a moment as he came over his ow stomach, a few drops ending up on his fingers as he went lax and practically sunk into the mattress.  
Jim let Sebastian have a moment to enjoy his... After orgasm but it was only because he was interested in the creamy stuff that was on Sebastian's stomach and he unashamedly ran a finger through it. 

"What's this? Will mine do this? What's it for? I want to do it. Can I? You should do it for me." Sebastian huffed out an irritated sigh before grabbing Jim, moving the thin body with ease until it was firmly pinned beneath him. 

"Stop asking so many fucking questions." Jim of course knew he was going to get what he wanted, he always did but he wasn't expecting that reaction and he was confused by the shiver than ran through his body, because it wasn't an entirely unpleasant shiver and the confusion must have shown in his eyes. 

"'M not gonna hurt you Jim." Even though Sebastian's words were reassuring a predatory grin crossed his face as his hand immediately found Jim's small hard length. He was amazed by how small it was under his fingers and his brain started to provide him with images of Jim impaled on his fingers as he licked over the hairless groin. 

Sebastian groaned at the thought while Jim gasped at the sensation of someone else touching him there for the very first time. He gasped again as he started to make rather involuntary sounds, breathy light versions of the sounds Sebastian had been making and he could certainly feel why. 

"It feels, ah~ it feels funny." 

"It's okay, let me take care of you, I said I would look after you Jim." Sebastian grinned again and rubbed his thumb over the small glistening tip of Jim's hard prick, watching the way Jim squirmed under him.  
"Shit, you look so pretty like that, such a pretty little desperate thing." Jim felt his face flush at the praise and he didn't know his body could feel like this and his hands scrambled to grasp at Sebastian's shoulders, just for something to hold onto. 

"S-Seb it feels like I-I’m gonna pee, I don't wanna!" Sebastian smiled at the way Jim grasped him and he kept moving his fingers over the short length. 

"It's okay, it's okay Jim, trust me." Jim only bit his lip and nodded, his body continuing to squirm as he felt a weird feeling in his stomach and he gasped, his fingers digging into Sebastian's shoulders. 

"I think, I think I'm gonna, I think-" Jim suddenly cried out, a sob escaping him as his small body experienced its first climax and only a few small drops of release escaped him. 

"It's okay, it's okay Jim I said I would look after you." Sebastian grinned as Jim's body trembled and he immediately moved his hand away, not wanting to overstimulate the boy and he stroked a hand over his slim waist.  
Jim didn't know how to react, he felt... Blissed out like that feeling you get when you’re so excited and it builds up until it plateaus and his body was still trembling so it took him a long while to calm down, taking an even longer while before he could speak again. 

"That was... That was new. I think I liked it." 

"You think? The way your body trembled and the sounds you made told me otherwise, they told me you loved it." Sebastian gave him a grin before moving away from the boy and nudging him lightly.  
"Come on, we're going to have to get cleaned up before your parents come and pick you up." At his comment it was like he was suddenly once again reminded of Jim's age and he chewed his lip, hoping Jim would keep him mouth shut. 

"Seb? Is there more things like that what you can do? With partners? Because I think I might get told off if I ask da or ma so I think maybe I should come back so you can tell me because I want to learn." 

"Kid, that was a one off. It shouldn't have happened at all so it won't happen again." 

"I promise I won't tell!" Sebastian groaned and rubbed a hand over his face. 

"Fine." What the fuck was he getting himself into?


End file.
